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United States Patent |
5,534,387
|
Bodager
,   et al.
|
July 9, 1996
|
Transfer process for forming a colored image utilizing a
non-photosensitive/photosensitive combination
Abstract
A process for forming on any printing stock, single colored and
multi-colored images using the expose-in-register and laminate-in-register
processes is described. Images having high quality, good resolution, and
color flexibility not heretofore economically feasible are obtained using
the process of the invention.
Inventors:
|
Bodager; Gregory A. (Monroeton, PA);
Beighle; Phillip L. (Colts Neck, NJ)
|
Assignee:
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E. I. Du Pont de Nemours and Company (Wilmington, DE)
|
Appl. No.:
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315739 |
Filed:
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September 30, 1994 |
Current U.S. Class: |
430/325; 430/252; 430/253; 430/258; 430/326 |
Intern'l Class: |
G03C 005/00 |
Field of Search: |
430/325,326,252,258,253
|
References Cited
U.S. Patent Documents
4272620 | Jun., 1981 | Ichimura | 525/61.
|
4737436 | Apr., 1988 | Thompson | 430/143.
|
4937168 | Jun., 1990 | Platzer | 430/257.
|
5094931 | Mar., 1992 | Platzer | 430/258.
|
5443937 | Aug., 1995 | Bodager et al. | 430/143.
|
Foreign Patent Documents |
1-116539 | May., 1989 | JP.
| |
1-116540 | May., 1989 | JP.
| |
Other References
International Publication No. WO 92/02857, published Feb. 20, 1992,
International Appln. No. PCT/US91/05387, International Filing Date Jul.
30, 1991, Inventors--Gregory Allen Bodager et al.
|
Primary Examiner: Lesmes; George F.
Assistant Examiner: Weiner; Laura
Claims
What is claimed is:
1. A process for forming a colored image comprising, in order:
(A) applying at least one aqueous-permeable, colorant-containing
composition to a photosensitive element comprising, in order,
(1) a carrier element having a release surface, said carrier element being
resistant to aqueous liquid development,
(2) a first adhesive layer,
(3) an unpigmented, first photosensitive layer consisting essentially of a
photosensitive composition which is developable by aqueous liquid which is
selected from water or an aqueous solution that consists essentially of
water, wherein the aqueous-permeable, colorant-containing composition is
applied to said first photosensitive layer;
(B) imagewise exposing to actinic radiation the photosensitive element from
step (A) having applied thereon the permeable, colorant-containing
composition to form imagewise exposed and unexposed regions in the
unpigmented, first photosensitive layer and the overlying permeable,
colorant-containing composition;
(C) developing the exposed element from step (B) by washing with an aqueous
liquid, thereby removing either the imagewise exposed or imagewise
unexposed regions of the unpigmented first photosensitive layer and its
overlying aqueous-permeable, colorant-containing layer, to produce a first
colored pattern;
(D) laminating to the element from step (C) a transfer element having a
release surface, wherein the release surface is adjacent to the first
colored pattern in the element from step (C);
(E) removing said carrier element having a release surface, revealing the
adhesive layer;
(F) laminating the element from step (E) to a permanent support, wherein
the adhesive layer is adjacent to the permanent support; and
(G) removing said transfer support having a release surface; wherein the
adhesion force between the release surface of said carrier element and
said adhesive layer has a value of F1; the adhesion force between said
adhesive layer and said first colored pattern has a value of F2; the
adhesion force between said first colored pattern and said release surface
of said transfer support has a value of F3; and the adhesion force between
said adhesive layer and said permanent support has a value of F4; and
wherein
each of F2 and F3 is greater than F1, and
each of F2 and F4 is greater than F3.
2. The process of claim 1 additionally comprising, in order following step
(C):
(C1) laminating to the element from step (C) an unpigmented element, said
unpigmented element comprising,
(1) an additional support,
(2) an underlying additional photosensitive layer comprising,
(a) an aqueous liquid developable, unpigmented, photosensitive composition,
and
(3) an underlying additional adhesive layer; wherein the additional
adhesive layer is adjacent to and overlying the first colored pattern in
the element from step (C);
(C2) removing said additional support;
(C3) applying at least one aqueous permeable colorant-containing
composition to the additional photosensitve layer;
(C4) imagewise exposing to actinic radiation said additional photosensitive
layer and the aqueous permeable colorant-containing composition in
register with the previously formed first colored pattern to form
imagewise exposed and imagewise unexposed regions;
(C5) developing said exposed additional photosensitive layer and the
aqueous permeable colorant-containing composition from step (C4) by
washing with an aqueous liquid, thereby removing either the imagewise
exposed or imagewise unexposed regions, to produce an additional colored
pattern; and optionally;
(C6) repeating, in order, steps (C1) to (C5) one or more times; wherein the
adhesion force between any of the additional photosensitive layers prior
to exposure to actinic radiation and its overlying additional support has
a value less than each of F1 and F2 and is less than each of the adhesion
forces between adhesive layers and adjacent photosensitive layers or
colored patterns; wherein the adhesion force between said additional
adhesive layer and said underlying first colored pattern has the value F5,
the adhesion force between any of said additional adhesive layers and the
underlying additional colored pattern has the value F5i, the adhesion
force between any of said additional adhesive layers and the overlying
additional colored pattern has the value F2i, the adhesion force between
the uppermost additional colored pattern and said release surface of said
transfer support has a value F3n, and the adhesion force between the
additional adhesive layer and the overlying additional photosensitive
layer prior to exposure to actinic light has the value F6, and wherein
each of F2, F3, F2i, F3n, F5, F5i and F6 is greater than F1, and
each of F2, F2i, F4, F5, F5i is greater than F3n.
3. The process of claim 1 wherein after step (E), steps (A) through (E) are
repeated at least once using at least one different aqueous permeable,
colorant-containing composition, a different photosensitive element, and
the element from step (E) as the transfer element in step (D).
4. The process of claim 1, 2 or 3 wherein the release surface on the
carrier element comprises a release layer.
5. The process of claim 1, 2 or 3 wherein the release surface on the
carrier element comprises a cushion layer.
6. The process of claim 5 wherein the photosensitive element further
comprises at least one carrier anchor layer between the carrier cushion
layer and the carrier element, wherein the adhesion force between the
carrier element and the carrier anchor layer, and the adhesion force
between the carrier anchor layer and the carrier cushion layer are
individually greater than F1.
7. The process of claim 1, 2 or 3 wherein the release surface on the
transfer element comprises at least one release layer.
8. The process of claim 7 wherein the release surface on the transfer
element comprises first and second release layers, the first release layer
being adjacent to the first colored pattern, and wherein the adhesion
force between the first colored pattern and the first release layer is
greater than the adhesion force between the first and second release
layers.
9. The process of claim 1, 2 or 3 wherein the release surface on the
transfer element comprises at least one cushion layer.
10. The process of claim 9 wherein the release surface on the transfer
element comprises first and second cushion layers, the first cushion layer
being adjacent to the first colored pattern, and wherein the adhesion
force between the first colored pattern and the first cushion layer is
greater than the adhesion force between the first and second cushion
layers.
11. The process of claim 9 wherein the photosensitive element further
comprises at least one transfer anchor layer between the transfer cushion
layer and the transfer support, wherein the adhesion force between the
transfer support and the transfer anchor layer, and the adhesion force
between the transfer anchor layer and the transfer cushion layer are
individually greater than F1, F3 and F3n.
12. The process of claim 5 wherein the carrier cushion layer comprises a
compound selected from the group consisting of ethylene/vinyl acetate
copolymers, ethylene homopolymers, propylene homopolmers,
ethylene/propylene copolymers, ethylene/methacrylate copolymers,
ethylene/methacrylic acid/isobutylacrylic acid ionomers,
ethylene/methacrylic acid copolymers, ethylene/methacrylic acid ionomers,
ethylene/acrylic acid copolymers, ethylene/acrylic acid ionomers, and
mixtures thereof.
13. The process of claim 9 wherein the at least one transfer cushion layer
comprises a compound selected from the group consisting of ethylene/vinyl
acetate copolymers, ethylene/methacrylate copolymers, ethylene/methacrylic
acid/isobutylacrylic acid ionomers, ethylene/methacrylic acid copolymers,
ethylene/methacrylic acid ionomers, ethylene/acrylic acid copolymers,
ethylene/acrylic acid ionomers, and mixtures thereof.
14. The process of claim 1, 2 or 3 wherein the carrier cushion layer
comprises a compound selected from the group consisting of
ethylene/methacrylic acid copolymers, ethylene/methacrylic acid ionomers,
ethylene/acrylic acid copolymers, ethylene/acrylic acid ionomers, and
mixtures thereof and the transfer cushion layer comprises an
ethylene/vinyl acetate copolymer.
15. The process of claim 1, 2 or 3 wherein the photosensitive composition
comprises a material selected from the group consisting of N-alkyl
styrylpyridinium derivatives of polyvinyl alcohol, N-alkyl
styrylquinolinium derivatives of polyvinyl alcohol, and mixtures thereof.
16. The process of claim 1, 2 or 3 wherein the adhesive layer comprises a
material selected from the group consisting of vinyl chloride/vinylacetate
copolymers, ethylene/vinylacetate copolymers, polyesters, and mixtures
thereof.
17. The process of claim 1, 2 or 3 wherein the aqueous liquid is water.
18. The process of claim 1, 2 or 3 wherein the aqueous permeable,
colorant-containing composition is applied as a layer.
19. The process of claim 1, 2 or 3 wherein the aqueous permeable
colorant-containing composition is absorbed into the unpigmented first
photosensitive layer.
20. The process of claim 1, 2 or 3 wherein the aqueous permeable
colorant-containing composition is printed on the unpigmented, first
photosensitive layer using an ink jet printer.
21. The process of claim 20 wherein the aqueous permeable
colorant-containing composition is an ink comprising an aqueous carrier
medium and a colorant.
22. The process of claim 21 wherein the colorant is a pigment dispersion.
23. The process of claim 21 wherein the colorant is a dye.
24. The process of claim 18 wherein the surface of the layer of the aqueous
permeable colorant-containing composition away from the unpigmented
photosensitive layer is matte-finished.
25. The process of 19 wherein the surface of the unpigmented photosensitive
layer having the aqueous permeable colorant-containing composition
absorbed therein is matte-finished.
26. The process of claim 1, 2 or 3 wherein the unpigmented photosensitive
layer is matte-finished prior to application of the aqueous permeable
colorant-containing composition.
Description
FIELD OF THE INVENTION
This invention relates to the formation of colored images. In particular,
this invention relates to the formation of a colored image, using an
unpigmented photosensitive element and a colorant-containing composition
applied thereon, and subsequent transfer of the image to any desired
support.
BACKGROUND OF THE INVENTION
Photosensitive elements which can be used in image-reproduction processes
are well-known in the graphics arts industry. Such elements are usually
exposed to actinic radiation through an image-bearing transparency, such
as a color separation transparency, to produce an image which is either a
positive or negative with respect to the transparency used.
Such photosensitive elements are widely used in off-press color proofing to
simulate the images produced by printing. In a surprint proof, all of the
colored images are superimposed, by, for example, multiple exposure,
lamination, or transfer, onto a single support. Unlike an overlay proof,
the colored images cannot be separated and viewed individually.
Various processes for producing copies of images involving
photopolymerization and thermal transfer techniques are known as disclosed
in U.S. Pat. Nos. 3,060,023; 3,060,024; 3,060,025; 3,481,736; 3,574,049
and 3,607,264. In these processes, a photopolymerizable layer coated on a
suitable support is imagewise exposed to a photographic transparency. The
surface of the exposed layer is then pressed into contact with the image
receptive surface of a separate element, and at least one of the elements
is heated to a temperature above the transfer temperature of the unexposed
portions of the layer. The two elements are then separated, whereby the
thermally transferable, unexposed, image areas of the composite, transfer
to the image receptive element. If the element is not precolored, the
tacky, unexposed image may now be selectively colored with a desired
toner. All of these processes necessitate the use of specially treated
final receptor sheets and are not applicable for obtaining a color
proofing image on a paper stock.
If the element is precolored, flexibility in your choice of colors is
limited because preparation of the precolored elements in all the desired
colors is not economically feasible. Toning provides greater color
flexibility but is associated with environmental concerns because the fine
powders are difficult to handle. Also, use of toners results in images
having significant relief so that it is difficult to obtain high
resolution images when it is necessary to superimpose images to make
multicolored images.
Precolored wash-off systems are known in the art. These include precolored
diazo based imaging systems such as Van Beusekom, U.S. Pat. No. 3,671,236;
Cederburg, U.S. Pat. No. 4,656,114; and Sachi, U.S. Pat. No. 4,666,817
which are developed in a mixture of water and 1-propanol; Krech, U.S. Pat.
No. 4,260,673 which is developed in base; and Platzer, U.S. Pat. No.
4,751,166, Mino, U.S. Pat. No. 4,783,390 and Adolphson et al., U.S. Pat.
No. 5,075,722 which are developed in water. These systems provide improved
resolution. However, the elements are precolored and thus, color
flexibility is limited because preparation of the precolored elements in
all the desired colors is not economically feasible. An additional
drawback for systems developed in aqueous base or organic solvents is that
they can pose flammability, toxicity, corrosion and/or waste disposal
concerns.
Thompson, U.S. Pat. No. 4,737,436 discloses a water based method for making
color proof images on a single substrate using a photoresist coating
containing a pigment blend. The process provides for the blending of
pigments, followed by the combining of the pigment blend with a water
soluble photoresist composition, coating a substrate with the photoresist
pigment-containing blend, imagewise exposing and developing to produce an
image on the substrate. A second image is then formed on the exposed and
developed substrate by forming a second pigment blend, followed by the
combining of the second pigment blend with a water soluble photoresist
composition, coating the substrate having the first image with the
photoresist second pigment-containing blend, imagewise exposing and
developing to produce a second image on the substrate. This process has
several disadvantages. First, combining the pigment blend with the
photoresist coating can result in coating solution stability problems.
Coating non-uniformity problems can result, with uniform coating becoming
increasingly difficult as the size of the work increases. Second, since
the pigment blend is mixed with the photoresist prior to coating,
compatiblity of the pigment with the photoresist coating becomes an issue.
This process is also limited in that it does not provide for the
application of colorant to the approximate image areas only.
A need exists for a process that generates a high resolution, high quality
color image on virtually any paper stock. Further, a need exists for a
process that provides color flexibility without the environmental concerns
associated with the previously mentioned proofing systems. A need also
exists for a process that provides for application of the colorant to the
approximate image areas only rather than the entire photosensitive layer.
SUMMARY OF THE INVENTION
This invention provides a process for forming a colored image, said process
comprising, in order:
(A) applying at least one aqueous permeable colorant-containing composition
to a photosensitive element comprising, in order,
(1) a carrier element having a release surface, said carrier element being
resistant to aqueous liquid development,
(2) a first adhesive layer,
(3) an unpigmented, first photosensitive layer consisting essentially of an
aqueous liquid developable photosensitive composition, wherein the aqueous
permeable colorant-containing composition is in contact with the first
photosensitive layer, wherein the aqueous permeable colorant-containing
composition is applied to (3);
(B) imagewise exposing to actinic radiation the photosensitive element from
step (A) having applied thereon the permeable colorant-containing
composition to form imagewise exposed and unexposed regions in the
unpigmented, first photosensitive layer and the overlying permeable
colorant-containing composition;
(C) developing the exposed element from step (B) by washing with an aqueous
liquid, thereby removing either the imagewise exposed or imagewise
unexposed regions, to produce a first colored pattern;
(D) laminating to the element from step (C) a transfer element having a
release surface, wherein the release surface is adjacent to the first
colored pattern in the element from step (C);
(E) removing said carrier element having a release surface, revealing the
adhesive layer;
(F) laminating the element from step (E) to a permanent support, wherein
the adhesive layer is adjacent to the permanent support; and
(G) removing said transfer element having a release surface; wherein the
adhesion force between the release surface of said carrier element and
said adhesive layer has a value of F1, the adhesion force between said
adhesive layer and said first colored pattern has a value of F2, the
adhesion force between said first colored pattern and said release surface
of said transfer support has a value of F3, and the adhesion force between
said adhesive layer and said permanent support has a value of F4; and
wherein
each of F2 and F3 is greater than F1, and
each of F2 and F4 is greater than F3.
Optionally, this process can be employed to form a multi-colored image. A
multi-colored image can be prepared by an expose-in-register process or by
a laminate-in-register process. In the expose-in-register process, the
process additionally comprises, in order following step (C):
(C1) laminating to the element from step (C) a photosensitive element
comprising in order,
(1) an additional support,
(2) an underlying additional photosensitive layer comprising,
(a) at least one aqueous developable, unpigmented, photosensitive
composition; and
(3) an underlying additional adhesive layer; wherein the additional
adhesive layer is adjacent to and overlying the first colored pattern in
the element from step (C);
(C2) removing said additional support;
(C3) applying at least one aqueous permeable colorant-containing
composition to the additional photosensitive layer;
(C4) imagewise exposing to actinic radiation said additional photosensitive
layer and the aqueous permeable colorant-containing composition in
register with the previously formed first colored pattern to form
imagewise exposed and imagewise unexposed regions;
(C5) developing said exposed additional photosensitive layer and the
aqueous permeable colorant-containing composition from step (C4) by
washing with an aqueous liquid, thereby removing either the imagewise
exposed or imagewise unexposed regions, to produce an additional colored
pattern; and optionally;
(C6) repeating, in order, steps (C1) to (C5) one or more times; wherein the
adhesion force between any of the additional photosensitive layers prior
to exposure to actinic radiation and its overlying additional support has
a value less than each of F1 and F2 and is less than each of the adhesion
forces between adhesive layers and adjacent photosensitive layers or
colored patterns; wherein the adhesion force between said additional
adhesive layer and said underlying first colored pattern has the value F5;
the adhesion force between any of said additional adhesive layers and the
underlying additional colored pattern has the value F5i; the adhesion
force between any of said additional adhesive layers and the overlying
additional colored pattern has the value F2i; the adhesion force between
the uppermost additional colored pattern and said release surface of said
transfer support has a value F3n; the adhesion force between the
additional adhesive layer and the overlying additional photosensitive
layer prior to exposure to actinic light has the value F6, and wherein
each of F2, F3, F2i, F3n, F5, F5i and F6 is greater than F1; and
each of F2, F2i, F4, F5, F5i is greater than F3n.
In the laminate-in-register process, after step (E), steps (A) through (E)
are repeated at least once using a different aqueous permeable,
colorant-containing composition, a different photosensitive element, and
the element from step (E) as the transfer element in step (D).
The invention also provides an imaged element comprising, in order:
(1) a carrier element having a release surface, said carrier element being
resistant to aqueous development;
(2) a first adhesive layer;
(3) a first colored pattern, resulting from the imagewise exposure and
washout development of a first unpigmented, photosensitive layer
comprising an aqueous liquid developable photosensitive composition and an
overlying aqueous permeable colorant-containing composition, wherein the
colorant-containing composition is present as a separate layer or absorbed
into the first unpigmented, photosensitive layer; and
(4) a transfer element having a release surface; wherein the adhesion force
between the release surface of said carrier element and said adhesive
layer has a value of F1, the adhesion force between said adhesive layer
and said first colored pattern has a value of F2, and the adhesion force
between said first colored pattern and said release surface of said
transfer support has a value of F3; and wherein
each of F2 and F3 is greater than F1, and
F2 is greater than F3.
In a preferred embodiment, the liquid for development is water; the
photosensitive material is an aqueous-processable derivative of polyvinyl
alcohol containing photocrosslinkable groups selected from the group
consisting of N-alkyl styrylpyridinium and N-alkyl styrylquinolinium; and
the aqueous colorant-containing composition is an ink jet ink that is
printed on or applied to the unpigmented, photosensitive layer using an
ink jet printer.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic illustration of the photosensitive element used in
the process of the invention having applied thereon at least one aqueous
permeable colorant-containing composition.
FIG. 2 is a schematic illustration of the carrier element used in the
process of the invention.
FIGS. 3 and 4 are schematic illustrations of alternate embodiments of the
transfer element which may be used in the process of the invention.
FIG. 5 is a schematic illustration of a single-color intermediate imaged
element.
FIG. 6 is a schematic illustration of a single-color image on a permanent
support prior to removal of the transfer element.
FIG. 7 is a schematic illustration showing an additional photosensitive
element having in order, an adhesive layer, a photosensitive layer and a
carrier element present on the first colored pattern containing element
after step (C) using the expose-in-register process.
FIG. 8 is a schematic illustration showing the first colored pattern
containing element after step (C) having in order, an adhesive layer, a
photosensitive layer and a aqueous permeable colorant-containing
composition present on it using the expose-in-register process.
FIG. 9 is a schematic illustration of a multicolor intermediate imaged
element using the expose-in-register process.
FIG. 10 is a schematic illustration of a multicolor image on a permanent
support prior to removal of the transfer element using the
expose-in-register process.
FIG. 11 is a schematic illustration of a final multicolor image on a
permanent support formed using the expose-in-register process.
FIG. 12 is a schematic illustration of a two color intermediate element
using the laminate-in-register process.
FIG. 13 is a schematic illustration of a multicolor intermediate element
using the laminate-in-register process.
FIG. 14 is a schematic illustration of a multicolor image on a permanent
support prior to removal of the transfer element using the
laminate-in-register process.
FIG. 15 is a schematic illustration of a final multicolor image on a
permanent support formed using the laminate-in-register process.
DETAILED DESCRIPTION OF THE INVENTION
In one embodiment of the invention, a single colored image on a permanent
support is formed by applying at least one aqueous permeable
colorant-containing composition to a photosensitive element comprising a
carrier element having a release surface, a first adhesive layer, and an
unpigmented, first photosensitive layer consisting essentially of an
aqueous liquid developable photosensitive composition, wherein the aqueous
permeable colorant-containing composition is applied to the photosensitive
layer; imagewise exposing to actinic radiation the photosensitive element
having applied thereon the permeable colorant-containing composition to
form imagewise exposed and unexposed regions in the unpigmented, first
photosensitive layer and the overlying permeable colorant-containing
composition; developing the exposed element by washing with an aqueous
liquid, thereby removing either the imagewise exposed or imagewise
unexposed regions, to produce a first colored pattern; laminating to the
exposed and developed element a transfer element having a release surface,
wherein the release surface is adjacent to the first colored pattern;
removing said carrier element having a release surface, revealing the
adhesive layer; laminating the element so formed to a permanent support,
wherein the adhesive layer is adjacent to the permanent support; and
removing said transfer support having a release surface.
In another embodiment of this invention, a carrier element is used to build
up a multicolored image consisting of multiple imaged color layers, each
interleaved and bonded together with an adhesive layer. Multiple color
images are built up on the carrier element by executing multiple imaging
steps, respectively. After the multicolored image has been formed, a
transfer element is employed to effect a double transfer of the
multicolored image, ending with transfer of the colored image from the
transfer element (which image is wrong-reading) to the permanent support
to afford a right-reading image. This process of forming a multicolored
surprint proof is called an expose-in-register process.
In still another embodiment of the invention, a multicolored surprint proof
is formed by exposing and developing at least one additional
photosensitive element comprising a carrier element having a release
surface, an adhesive layer and an unpigmented photosensitive layer, and
which has applied thereon at least one aqueous permeable
colorant-containing composition, laminating in register the so formed
colored image to a transfer element having a first colored image thereon,
followed by removal of the carrier element having a release surface and
lamination of the so formed multicolor image to a permanent support. This
process of forming a multicolored surprint proof is called a
laminate-in-register process.
This invention provides for high resolution, high quality, full color
surprint proofs on virtually any proofing paper stock or other permanent
support. It also provides for development during imaging with tap water as
the liquid developer to minimize or eliminate concerns regarding toxicity,
waste treatment, and corrosion. It also provides for color flexibility and
the capability for addition of the colorant-containing composition only to
the approximate areas where an image is desired. It also provides for the
addition of more than one color to a single layer.
In practicing the process of the invention, at least four components are
necessary: (I) a photosensitive element comprising in order an adhesive
layer and a photosensitive layer on a carrier element having a release
surface, (II) an aqueous permeable colorant-containing composition, (III)
a transfer element, and (IV) a permanent support element. The carrier
element having a release surface may comprise a carrier support and a
release layer or a cushion layer. The transfer element having a release
surface comprises a transfer support and at least one release layer or
cushion layer. Additional photosensitive elements and additional
colorant-containing compositions are also used in making multicolor
images.
In order to facilitate understanding of the process of the invention, the
individual components will be described in detail first.
PHOTOSENSITIVE ELEMENT
The photosensitive element is shown in FIG. 1. The element comprises, in
order, a carrier element having a release surface (10), an adhesive layer
(11), and a photosensitive layer (12).
Carrier Element
The carrier element having a release surface (10) may comprise a carrier
support (14) and a surface layer (15) which may be a release layer or a
cushion layer. If the material used as the carrier support has a release
surface, e.g., polyethylene or a fluoropolymer, no additional surface
layer is needed. The carrier surface layer (15) should have sufficient
adhesion to the carrier support (14) to remain affixed to that support
throughout all the process steps in the processes of the invention. The
carrier surface layer should have sufficient adhesion to the adhesive
layer to remain affixed thereto during aqueous development of the
photosensitive layer. But at the same time, the adhesion of the carrier
surface layer to the adhesive layer should be low enough to allow for
removal of the carrier support and the carrier surface layer, if present,
subsequent to the aqueous development steps. The relative adhesion
balances will be discussed in greater detail below.
In the single color image process and the expose-in-register multicolor
image process, the carrier element serves as a temporary receptor upon
which the colored image, comprising one or more imaged colored layers
interleaved with adhesive layers, can be constructed. The photosensitive
layer with its overlying aqueous permeable colorant-containing composition
is exposed and developed while on the carrier element.
The carrier support (14) can comprise almost any material which has
reasonable stiffness, has dimensional stability, and is water resistant.
Materials with sufficient stiffness and dimensional stability are those
which are capable of supporting an image without allowing it to shift and
misalign. The material used for the carrier support should have enough
water resistance to allow for aqueous development of the photosensitive
layer without warping or shrinking. The material used for the carrier
support should also have sufficient heat and pressure resistance to
withstand the various lamination steps. The support is generally smooth
and flat. Examples of suitable materials which can be used include
polymeric films such as polyesters, including polyethylene terephthalate
and polyethylene naphthanate; polyamides; polycarbonates; fluoropolymers;
polyacetals; polyolefins; etc. The carrier support can also be a thin
metal sheet or a paper substrate or synthetic paper which has been treated
to be water resistant. The carrier support can be transparent, translucent
or opaque. It can be colored and can have incorporated within materials
such as antihalation dyes, etc. A preferred carrier support material is
polyethylene terephthalate film.
The carrier support can have an antistat layer coated on one or both sides.
This can be useful in reducing static when the carrier support is removed
from the photosensitive element by peeling off, as will be discussed
below. It is generally preferred to have an antistat layer coated on the
back side of the carrier support, i.e., the side opposite from that on
which the photosensitive layer is present. Materials which can be used as
antistat materials are well known in the art.
The carrier support typically has a thickness of about 20 to about 250
micrometers (1.0 to 10 mils). A preferred thickness is about 55 to 200
micrometers (2 to 8 mils).
The release surface of the carrier element may be provided by a surface
layer (15) which is selected from the group consisting of (i) a release
layer and (ii) a cushion layer. Release layers are generally very thin
layers which promote the separation of layers. Materials useful as release
layers are well known in the art and include, for example, silicones;
melamine acrylic resins; vinyl chloride polymers and copolymers; vinyl
acetate polymers and copolymers; plasticized polyvinyl alcohols; ethylene
and propylene polymers and copolymers; etc. When a separate release layer
is coated onto the carrier support, the layer generally has a thickness in
the range of 0.5 to 10 micrometers.
The carrier release layer may also include materials such as antistats,
colorants, antihalation dyes, optical brighteners, surfactants,
plasticizers, coating aids, matting agents, and the like.
A second, and preferred, type of carrier surface layer (15) is a cushion
layer having a release surface. The cushion layer is a deformable layer
which is generally thicker than a release layer. Surprisingly, it was
found that the incorporation of a carrier cushion layer on the carrier
support resulted in several advantages in the process of the invention
when forming multicolor images: the amount of mottle caused by
incorporation of entrapped air during lamination steps was greatly
reduced; lamination temperatures could be reduced; and the adhesion
between colors was improved.
The carrier cushion layer should have a release surface to allow for
separation of the carrier support and carrier cushion layer from the
adhesive layer subsequent to aqueous development of the photosensitive
layer. Some examples of suitable materials which can be used as the
carrier cushion layer include ethylene/methacrylic acid copolymers and
ionomers; ethylene/acrylic acid copolymers and ionomers; ethylene/vinyl
acetate copolymers; ethylene homopolymers; propylene homopolymers;
ethylene/propylene copolymers; ethylene/methacrylate copolymers;
ethylene/methacrylic acid/isobutylacrylic acid ionomers; and the like.
Mixtures of materials can also be used. Preferred materials for the
carrier cushion layer are ethylene/methacrylic acid and ethylene/acrylic
acid copolymers and ionomers. Such materials are commercially available
as, e.g., Surlyn.RTM. 1601 (E. I. du Pont de Nemours and Company,
Wilmington, Del.) and Iotek.RTM. 4080 (Exxon Chemical Co., Houston, Tex.).
The carrier cushion layer may also include materials such as antistats,
colorants, antihalation dyes, optical brighteners, surfactants,
plasticizers, coating aids, and the like. In general, these additional
materials may constitute less than about 10% by weight, based on the total
weight of the carrier cushion layer; preferably less than about 5% by
weight. It can be advantageous to include a white pigment in the carrier
cushion layer. This facilitates inspection of the colored image formed
thereon.
The carrier cushion layer generally has a thickness in the range of about
12 to 150 micrometers (0.5 to 6 mils); preferably 35 to 65 micrometers
(1.4 to 2.6 mils).
In order to ensure adequate adhesion of the carrier cushion layer to the
carrier support, it is sometimes necessary to include one or more anchor
layers between them. By "anchor layer" it is meant a layer that remains
adhesively bonded to the layers on both sides, i.e., the layer above it
and the layer below it. Adhesive materials for bonding different types of
materials are well known in the art and discussions can be found in, e.g.,
Handbook of Adhesives, 2nd Edition, Irving Skeist, Ed. (Van Nostrand
Reinhold Co., New York, 1977). Any conventional adhesive materials can be
used in the anchor layer or layers so long as they are not adversely
affected by the aqueous development step. Suitable materials for use as
the carrier anchor layer include, for example, ethylene/vinyl acetate
copolymers; vinyl chloride/vinyl acetate copolymers; vinyl
chloride/vinylidene chloride copolymers; thermoplastic polyamides; and the
like. The exact choice of adhesive will depend on the compositions of the
carrier cushion layer and the carrier support. The anchor layer or layers
can have incorporated therein materials such as antistats, colorants,
antihalation dyes, optical brighteners, surfactants, plasticizers, coating
aids, and the like.
The carrier anchor layer generally has a thickness in the range of 0.01 to
10 micrometers; preferably 0.05 to 5 micrometers. When more than one
anchor layer is present, the total thickness of the layers is generally in
the above range.
The carrier element may also be provided with a temporary coversheet (not
shown). The temporary coversheet can comprise any material which affords
adequate protection of the underlying adhesive layer and which cleanly
releases from the adhesive layer by peeling. Preferred coversheets are
self releasing films, such as polyethylene or polyethylene terephthalate.
These films can be coated with release layers, such as silicone, so long
as the release layer is removed cleanly with the film. The thickness of
the temporary coversheet is not critical and typically is in the range of
25 to 250 micrometers (1 to 10 mils).
Adhesive Layer
The adhesive layer (11) remains affixed to the photosensitive layer
throughout the process of the invention. This adhesive layer can be
comprised of any suitable composition which has the necessary adhesion to
the photosensitive layer and which does not interfere with the function of
the photosensitive layer, such as, for example, might result from the
leaching of components from the adhesive layer into the photosensitive
layer or the resulting imaged layer. To provide a high resolution image,
it is preferred that the adhesive layer be capable of holding onto a dot
during processing; not stain the pigmented layer; and not block to other
layers, e.g. paper, etc., both during and after proof assembly.
Preferably, the adhesive layer is transparent and does not have any
yellowness which may shift the color balance. It should be capable of easy
lamination without trapping air bubbles which reduce image quality. It is
preferred that the adhesive layer be capable of sliding easily over other
layers, but not so easily that registration problems occur. The adhesive
layer should, preferably, heat seal to other color films and adhesive
layers, be scratch and abrasion resistant, in wet or dry form, and not
crack or become brittle over time, or when folded, bent, etc. Sticking to
components of the lamination or processing equipment is also undesirable.
As discussed above, adhesive materials for bonding different types of
materials are well known in the art and discussions can be found in, e.g.,
Handbook of Adhesives, 2nd Edition, Irving Skeist, Ed. (Van Nostrand
Reinhold Co., New York, 1977). The exact choice of adhesive will depend on
the nature of the photosensitive layer, the carrier support and the
release or cushion layers. Examples of some suitable types of adhesives
which can be used include polyester resins and vinylacetate copolymers
with ethylene and/or vinyl chloride.
Conventional additives listed earlier as additives for the cushioning and
release layers may also be present in the adhesive layer.
The adhesive layer (11) generally has a thickness in the range of 0.1 to 10
micrometers; preferably 0.5 to 3 micrometers.
Unpigmented Photosensitive Layer
The photosensitive layer (12) comprises an aqueous liquid developable
photosensitive composition for which exposure to actinic radiation results
in a change in solubility. The photosensitive composition can be
photoinsolubilizable, i.e., before exposure the photosensitive composition
is removable from the carrier support by water or by aqueous solutions
that consist essentially of water. After exposure, the composition is not
removable from the carrier support by water or by aqueous solutions that
consist essentially of water. Alternatively, the photosensitive
composition can be photosolubilizable. In this latter case, before
exposure the photosensitive composition is not removable from the support
by water or by aqueous solutions that consist essentially of water. After
exposure, the composition is removable from the support by water or by
aqueous solutions that consist essentially of water.
Photoinsolubilization is generally achieved by photoinitiated
polymerization and/or crosslinking reactions. The resulting change in
physical properties of the compounds present, particularly the increase in
molecular weight and/or network formation, insolubilizes the
photosensitive material.
Derivatives of water soluble polymers, such as polyvinyl alcohol, which
comprise pendant photocrosslinkable groups can be used to advantage in the
photosensitive layer. On exposure these groups react to form crosslinks
between different polymer chains. Photocrosslinkable polymers are
described in A. Reiser, Photoreactive Polymers: The Science and Technology
of Resists, Wiley, New York, 1989, pp 24-32. Typical photocrosslinkable
groups are, for example, the cinnamyl, chalcone, alpha-phenylmaleimide,
N-alkyl styrylpyridinium, and N-alkyl styrylquinolinium groups. Other
aqueous developable systems are disclosed in Briney et al., U.S. Pat. No.
4,485,167 issued Nov. 27, 1984.
Derivatives of polyvinyl alcohol which comprise photocrosslinkable groups
are preferred. Preferred polyvinyl alcohol derivatives are those which
comprises N-alkyl styrylpyridinium or N-alkyl styrylquinolinium groups.
Such polymers are described in K. Ichimura and S. Wantanabe, J. Polym.
Sci., Polym. Lett. Ed., 18, 613 (1980) and 20, 1411, 1419 (1982) as well
as in Ichimura, U.S. Pat. Nos.: 4,272,620, 4,287,335, 4,339,524, 4,564,580
and 4,777,114. The disclosure of these references is incorporated herein
by reference.
Substituted aqueous-processable polyvinyl alcohol polymers are typically
prepared by derivatization of saponified polyvinyl acetate with the
appropriate photocrosslinking group. It is desirable for the polyvinyl
acetate to be at least 70% hydrolyzed. Typically 88% saponified polyvinyl
acetate is used, but polyvinyl acetate which is more or less highly
saponified can be used provided the photosensitive layer is
aqueous-processable. The photocrosslinkable group can be attached to the
polyvinyl alcohol by any appropriate chemical linkage, such as an ester,
ether, or acetal linkage. The acetal linkage is preferred. Typically the
0.5-10 mol % photocrosslinkable groups, preferably 1-4 mol %, are present.
Although polymers containing higher amounts of photocrosslinkable groups
typically cannot be made to be aqueous-processable, higher amounts of
photocrosslinkable groups can be used, provided the photosensitive layer
is aqueous-processable. The degree of polymerization of the polyvinyl
alcohol, i.e., the number of monomer units in the polymer chain, is
advantageously in the range of 400 to 3,000. When the polymerization
degree is too low, the exposure time required for insolubilization is
lengthened. When the polymerization degree is too large, the viscosity of
solutions containing the polymer becomes so large that they are difficult
to prepare and handle.
Another class of polyfunctional photoactivatable crosslinking agents are
bis-azides. These compounds are typically aromatic bis-azides substituted
with one or more ionic groups, such as sulfonate, carboxylate, sulfate,
etc., to increase water solubility. Typical bis-azides are sodium
4,4'-diazidostilbene-2,2'-disulfonate, sodium
4,4'-diazidobenzalacetophenone-2-sulfonate, and sodium
4,4'-diazidostilbene-alpha-carboxylate. A preferred bis-azide is sodium
4,4'-diazidostilbene-2,2'-disulfonate. As will be apparent to those
skilled in the art, equivalent results may be obtained from the use of
bis-azides which contain other cations in place of sodium, such as, for
example, potassium, ammonium, and substituted ammonium, such as, for
example, ethyl ammonium, tetramethyl ammonium, etc.
Photosensitive diazo resins are another class of photosensitive materials.
These materials typically consist of aromatic diazonium salts crosslinked
with formaldehyde. Representative materials are: the zinc chloride complex
of the 4-(phenylamino)-benzenediazonium sulfate (1:1) formaldehyde
polymer, the zinc chloride complex of the 4-(phenylamino)-benzenediazonium
phosphate (1:1) formaldehyde polymer, the cobalt chloride complex of the
4-(phenylamino)-benzenediazonium (1:1) formaldehyde polymer, the
uncomplexed 4-(phenylamino)-benzenediazonium phosphate (1:1) formaldehyde
polymer, and the uncomplexed 4-(phenylamino)-benzenediazonium sulfate
(1:1) formaldehyde polymer. Since their development does not produce
effluent containing heavy metals, the uncomplexed
4-(phenylamino)-benzenediazonium phosphate (1:1) formaldehyde polymer and
the uncomplexed 4-(phenylamino)-benzenediazonium sulfate (1:1)
formaldehyde polymer are preferred.
Photosolubilization is generally achieved by photoinitiated conversion of
materials to more soluble forms, plasticization reactions,
depolymerization, uncoupling or uncrosslinking reactions. Systems based on
o-quinone diazides and low molecular weight phenolformaldehyde polymers
can be used to advantage. Upon exposure to ultraviolet radiation, the
o-quinone diazide is converted to the readily dissolved indene carboxylic
acid. A discussion of such systems can be found in A. Reiser,
Photoreactive Polymers: The Science and Technology of Resists, Wiley, New
York, 1989, pp 178-225. Useful photosolubilization chemistry is also
disclosed in Chen et al., U.S. Pat. No. 5,071,731.
Other conventional additives can also be added to the photosensitive layer
provided they are compatible with the other ingredients present in the
layer, do not impart unwanted color to the final image, and do not
adversely affect the action of the element required for the operation of
either the imaging process or the multiple transfers required to transfer
the image to a permanent support. In some cases separate photoinitiators
are added. Other components can include, for example, polymeric binders,
plasticizers, antihalation agents, optical brightening agents, release
agents, surfactants, coating aids, matting agents, and the like.
Additives may be included in the photosensitive composition to improve the
aqueous permeable, colorant-containing composition's penetration,
absorption and/or fixation to the photosensitive layer. Matting agents
added to the unpigmented photosensitive layer would be expected to provide
a matte appearance to the layer and may also provide improved
diffusibility of the colorant-containing composition into the unpigmented
photosensitive layer.
The photosensitive material must be present in sufficient amount to
solubilize or insolubilize the photosensitive layer on exposure to actinic
radiation. The photosensitive composition must contain sufficient polymer,
either as part of the photosensitive material and/or as added binder, to
form a film when coated to form the photosensitive layer. Other
ingredients may be present in amounts necessary to achieve their desired
purposes, but not in such large amounts that they adversely affect the
properties of the imaging system.
The composition of the photosensitive layer, expressed in percent by
weight, based on the total weight of the photosensitive layer, is
typically: binder 80-98%, preferably 85-96%; photosensitive material
2-10%, preferably 2-6% and other ingredients 0-10%. If no binder is
present, i.e., the photosensitive material also functions as a binder, the
composition is typically: photosensitive material 80-100%, preferably
90-100%; and other ingredients 0-20%.
The photosensitive layer generally has a thickness in the range of 0.1 to
10 micrometers; preferably 0.5 to 2 micrometers.
Preparation of the Photosensitive Element
The photosensitive element may be made by coating all of the layers, in
order, onto the carrier support using any conventional coating and/or
lamination techniques. Such processes are well known in the art. If the
adhesive layer is coatable from a non-aqueous solution, the layers may be
coated on the temporary coversheet (not shown) and laminated to the
carrier element. If so, the temporary cover sheet may have a matte finish
on its surface adjacent the photosensitve layer to impart a matte finish
to the photosensitive layer when the temporary cover sheet is peeled off.
It is frequently convenient to prepare the photosensitive element by
laminating together a preformed element to a carrier element. The
preformed element may comprise the photosensitive layer and the adhesive
layer sandwiched between a temporary coversheet (not shown) and a
temporary support (not shown). The adhesive layer (11) and the
photosensitive layer (12) have the same composition as discussed above.
The optional temporary coversheet is present to protect the element from
being scratched or otherwise damaged prior to use. The temporary
coversheet can be selected from the same materials described for the
temporary coversheet in the carrier element.
The temporary support can comprise any dimensionally stable sheet material.
Typically a polymeric film is used.
The support should be removable from the photosensitive layer prior to
exposure to actinic radiation. At the same time, there must be sufficient
adhesion between the photosensitive layer and the temporary support to
allow for manufacture and handling of the photosensitive element. A
separate release layer can be situated between the temporary support and
the photosensitive layer, or a silicone release-treated film can be used.
It is preferred to use a release layer. This allows for adjustment of the
adhesion force between the photosensitive layer and the temporary support
with respect to the other important adhesion forces which influence the
process of the invention, as will be discussed in detail below.
The thickness of the temporary support must be sufficient to impart the
necessary stiffness for handling and dimensional stability, but beyond
that it is not particularly critical. The thickness is generally in the
range of 25 to 250 micrometers (1 to 10 mils).
Preferably, the element having a temporary support and a temporary
coversheet is prepared by coating each of the individual layers onto the
temporary support. Preferably, the photosensitive layer is prepared by
suspending or dissolving the ingredients in an appropriate solvent,
preferably aqueous; coating onto the temporary support; and evaporating
the solvent.
The photosensitive element shown in FIG. 1 may be prepared from the
preformed element and the carrier element by laminating the two together.
The two temporary coversheets are first removed and the two elements
placed together such that the adhesive layer (11) is adjacent to the
carrier element (10). The temperature and pressure used in the lamination
step will depend on the composition of the adhesive layer (11) and the
carrier element (10). The temporary support is then peeled off. When a
release layer is present between the temporary support and the
photosensitive layer, the release layer will be peeled off with the
temporary support and will not remain on the photosensitive layer.
It will be clear to those skilled in the art that in order to remove the
two temporary coversheets, the adhesion force between each of the
temporary coversheets and their adjacent layers must be lower than the
adhesion forces between all the other layers in their respective elements.
It will also be clear that in order to remove the temporary support and
the associated release layer, if present, after the lamination step, the
adhesion force between the photosensitive layer and the temporary support
or the release layer, if present, must be lower than the adhesion force
between the photosensitive layer (12) and the adhesive layer (11), and the
adhesion force between the adhesive layer (11) and the carrier element
(10).
COLORANT-CONTAINING COMPOSITION
The aqueous permeable colorant-containing composition (13) is applied over
the unpigmented photosensitive layer of the photosensitive element. It may
be applied as a layer or may be absorbed into the photosensitive layer
after its application. The colorant-containing composition (13) has to be
aqueous permeable so as not to interfere with the development of the
photosensitive layer after exposure. If present as a layer over the
unpigmented photosensitive layer its thickness should be no greater than 4
micrometers, preferably no greater than 2 micrometers. The colorant used
may be any material that is insoluble in the aqueous liquid used to
develop the exposed, unpigmented photosensitive layer. The colorant can be
one of the four standard colors, i.e., yellow, magenta, cyan, and black,
or any other desired color. The colorants which can be used are well known
to those skilled in the art. The colorant should be compatible with the
photosensitive layer and preferably should not strongly absorb radiation
in the spectral range in which the photosensitive composition absorbs
radiation. Preferred colorants are pigments which are dispersible in
water.
The colorant must be present in a sufficient amount to uniformly color the
image to a sufficient optical density, but not in such a large amount that
if it were absorbed into the photosensitive layer after its application,
would adversely affect the properties of the photosensitive layer, for
example, photospeed, adhesion, etc., needed for the operation of the
imaging system. For surprint proofs, optical densities between 0.5 and 2
are desirable. Other ingredients may be included in the
colorant-containing composition to improve its penetration, absorption and
or fixation to the photosensitive layer provided they do not adversely
affect the photosensitive layer's imaging function or the colorant's
desired color. Water insoluble binders may be present in the aqueous
permeable colorant-containing composition to improve coatability and/or
water-fastness of the image.
The aqueous permeable colorant-containing composition (13) which typically
comprises a colorant and water may be coated, laminated, sprayed or
printed onto the unpigmented photosensitive layer. In the preferred
embodiment, the aqueous permeable colorant-containing composition (13) is
an ink jet ink and is applied using an ink jet printer. The ink jet ink
comprises an aqueous carrier medium and a colorant which may be a pigment
dispersion or a dye. If the colorant is a dye, it must be rendered
insoluble by known techniques, e.g. encapsulation, so it is not washed
away in the development step. Reactive dyes that are capable of reacting
with the photosensitive material upon exposure to UV radiation are also
useful in this invention. A dye dispersion may lso be used. The pigment
dispersion comprises a pigment and a dispersing agent, which preferably is
a polymeric compound.
INK JET INK
The aqueous permeable colorant-containing composition (13) which may be
applied as an ink jet ink comprises an aqueous carrier medium and a
colorant which may be a pigment dispersion or a dye.
Aqueous Carrier Medium
The aqueous carrier medium is water or a mixture of water and at least one
water-soluble organic component. Deionized water is commonly used.
Representative examples of water-soluble organic solvents are disclosed in
Ma et al., U.S. Pat. No. 5,085,698, the disclosure of which is
incorporated herein by reference. Selection of a suitable mixture of water
and water-soluble organic solvent depends upon requirements of the
specific application, such as desired surface tension and viscosity, the
selected pigment, drying time of the pigmented ink jet ink, and the type
of photosensitive layer onto which the ink will be printed. A mixture of a
water-soluble organic solvent having at least 2 hydroxyl groups, e.g.
diethylene glycol, and deionized water is preferred as the aqueous medium.
In the case of a mixture of water and diethylene glycol, water could be
present in the amount of between 30% and 95%, preferably 60% to 95%, by
weight based on the total weight of the aqueous carrier medium.
Colorant
The colorant useful in the invention may be a pigment dispersion or a dye.
A pigment is a colorant that is applied in an insoluble particulate state.
A dye is a colorant that is typically in a soluble state but will be
insolubilized by known techniques such as encapsulation prior to use in
this invention. Reactive dyes that are capable of reacting with the
photosensitive material upon exposure to UV radiation are also useful in
this invention. Disperse dyes may also be used. The term pigment
dispersion, as is known in the art and as used herein, refers to a mixture
of a pigment and a dispersing agent. Preferably, the dispersing agent is a
polymeric compound.
Pigments
Useful pigments for the dispersion comprise a wide variety of organic and
inorganic pigments, alone or in combination. For ink jet ink applications,
the pigment particles need to be sufficiently small to permit free flow of
the ink through the ink jet printing device, especially at the ejecting
nozzles that usually have a diameter ranging from 10 to 50 microns. The
particle size also has an influence on the pigment dispersion stability,
which is critical throughout the life of the ink. Brownian motion of
minute particles will help prevent the particles from flocculation. It is
also desirable to use small particles for maximum color strength and
gloss. The range of useful particle size is approximately 0.005 to 15
microns. Preferably, the pigment particle size should range from 0.005 to
1 micron.
The selected pigment may be used in dry or wet form such as presscake.
Representative commercial dry and presscake pigment that may be used in
practicing the invention are disclosed by Ma et al. in U.S. Pat. No.
5,085,698, which is incorporated herein by reference.
In the case of organic pigments, the ink may contain up to approximately
30% pigment by weight, but will generally be in the range of approximately
0.1 to 15%, preferably approximately 0.1 to 5%, by weight of the total ink
composition. If an inorganic pigment is selected, the ink will tend to
contain higher weight percentages of pigment because inorganic pigments
generally have higher specific gravities than organic pigments.
Dispersant
Polymeric dispersants are the preferred dispersants for pigments. Polymeric
dispersants suitable for practicing this invention include random
copolymers, block copolymers such as AB, BAB, and ABC block copolymers,
and graft copolymers.
In AB or BAB block copolymers, the A block is a hydrophobic homopolymer or
copolymer which serves to link with the pigment and the B block is a
hydrophilic homopolymer or copolymer, or salts thereof, which serves to
disperse the pigment in the aqueous medium. Such polymeric dispersants and
their synthesis are disclosed in Ma et al., U.S. Pat. No. 5,085,698,
issued Feb. 4, 1992, the disclosure of which is incorporated herein by
reference.
ABC triblock copolymers are also useful as pigment dispersants. In the ABC
triblock copolymer, the A block is a polymer soluble in water, the B block
is capable of binding to the pigment, and the C block is compatible with
the organic components in the ink. ABC triblock copolymers and their
synthesis are disclosed in Ma et al., U.S. Ser. No. 07/838,181 filed Feb.
20, 1992, the disclosure of which is incorporated herein by reference.
Although random copolymers can be used as dispersing agents, they are not
as effective in stabilizing pigment dispersions as the block copolymers,
and therefore are not preferred.
Dyes
Dyes which are commonly used in aqueous ink jet inks, such as, for example,
acid dyes, basic dyes, direct dyes, food dyes, and reactive dyes are
suitable colorants for the ink compositions of the present invention
provided they are rendered insoluble by techniques known to those skilled
in the art, e.g. encapsulation. Disperse dyes may also be suitable as
colorants.
The color and amount of dye used in the ink are largely a function of
choice, being primarily dependent upon the desired color of the print
achieved with the ink and the dye's strength. Low concentrations of dyes
may not give adequate color vividness. High concentrations may result in
poor printhead performance or unacceptably dark colors.
The dye may be present in the amount of 0.01 to 20%, by weight, preferably
0.05 to 8%, by weight, more preferably 1 to 5% by weight, based on the
total weight of the ink.
Other Ingredients
Any material that would provide swelling of the photosensitive layer
without having a deleterious effect on it would be useful for improving
diffusibility of the ink into the photosensitive layer, e.g. water,
surfactants, etc. Surfactants alter surface tension and would therefore be
expected to maximize penetration of the ink into the photosensitive layer.
However, they may also destabilize the pigment dispersion for pigmented
inks. The choice of a specific surfactant is also highly dependent on the
type of photosensitive layer in the photosensitive element to be printed.
One skilled in the art can select the appropriate surfactant and the
appropriate amount for a specific element to be printed. Thermal
crosslinking agents may be added to the ink or the photosensitive layer to
improve adhesion of the ink to the photosensitive layer and prevent it
from being washed off during the development step.
Biocides, sequestering agents such as EDTA, humectants, viscosity
modifiers, and other acrylic or non-acrylic polymers may also be added to
improve various properties of the inks.
Ink Preparation and Ink Properties
The aqueous permeable, colorant-containing ink compositions of the
invention are prepared as described in Ma et al., U.S. Pat. No. 5,085,692
issued Feb. 4, 1992.
Jet velocity, separation length of the droplets, drop size, and stream
stability are greatly affected by the surface tension and the viscosity of
the ink. Inks suitable for use with ink jet printing systems should have a
surface tension in the range of about 20 dyne/cm to about 70 dyne/cm and,
more preferably, in the range of 25 dyne/cm to about 70 dyne/cm at
20.degree. C. Acceptable viscosities are no greater than 20 cP, and
preferably below 10 cP at 20.degree. C. The ink has physical properties
compatible with a wide range of ejecting conditions, i.e., driving
voltage, driving frequency, and pulse width for thermal ink jet printing
devices, driving frequency for the piezo element for either a
drop-on-demand device or a continuous device, and the shape and size of
the nozzles, etc. They may be used with a variety of ink jet printers such
as continuous, piezoelectric drop-on-demand, and thermal drop-on-demand,
and are particularly adapted for use in thermal ink jet printers. The inks
have excellent storage stability for a long period and do not clog the
nozzles. Drying of the ink on the photosensitive layer can be carried out
rapidly and accurately by means known to those skilled in the art.
TRANSFER ELEMENT
The function of the transfer element having a release surface (16) is to
serve as a temporary receptor to receive the colored image after it has
been formed on the carrier support and to provide adequate support for the
image to maintain its integrity until it has been transferred to the
permanent support.
Representative transfer elements are shown in FIGS. 3 and 4. As shown in
FIG. 3, the element may comprise, in order, an optional temporary
coversheet (not shown), a transfer surface layer (18), and a transfer
support (17). Optionally, the transfer element may comprise a transfer
support (17) and two transfer surface layers (18) and (19). However, if a
material having a release surface is used as the transfer support (e.g.
polyethylene or a fluoropolymer) no additional release layer is needed.
The transfer support (17) may comprise almost any material which has
reasonable stiffness and dimensional stability. Materials with sufficient
stiffness and dimensional stability are those which are capable of
supporting an image without allowing it to shift and misalign. The support
is generally smooth and flat. Examples of suitable materials which can be
used include polymeric films such as polyesters, including polyethylene
terephthalate and polyethylene naphthanate; polyamides; polycarbonates;
fluoropolymers; polyacetals; polyolefins; etc. The transfer support can
also be a thin metal sheet or a paper substrate or synthetic paper. A
preferred transfer support material is polyethylene terephthalate film.
The transfer support typically has a thickness of about 20 to about 250
micrometers (1.0 to 10 mils). A preferred thickness is about 75 to 200
micrometers (3 to 8 mils).
The transfer surface layers (18) and (19) are selected from the group
consisting of (i) a release layer and (ii) a cushion layer. The transfer
surface layer (18) should have sufficient adhesion to the transfer support
to remain affixed to that support throughout all the process steps in the
process of the invention. At the same time, the adhesiveness of the
transfer surface layer should be carefully balanced with the adhesiveness
of the carrier surface layer in order to carry out the transfer steps in
the process of the invention. The relative adhesion balances will be
discussed in greater detail below.
In the embodiment wherein the transfer support (17) has two layers thereon,
adhesion of the layer (18) adjacent the support (17) may be greater than
its adhesion to layer (19). Layer (19) may have greater adhesion to the
exposed and developed photosensitive layer (12') having thereon the
aqueous colorant-containing composition (13') so that when the transfer
support is peeled off, layer (18) is removed with the support and layer
(19) is left behind. The two layer transfer element may also be designed
wherein both layers have greater adhesion to the support (17) than the
developed photosensitive layer (12') having thereon the aqueous
colorant-containing composition (13') so that when the transfer support
(17) is peeled off both layers (18) and (19) are removed with it. The two
layer transfer element may also be designed wherein both layers have
greater adhesion to the developed photosensitive layer (12') having
thereon the aqueous colorant-containing composition (13') than the support
(17) so that when the transfer support (17) is peeled off both layers (18)
and (19) are left behind on the developed photosensitive layer (12')
having thereon the aqueous colorant-containing composition (13').
As discussed above in conjunction with the carrier surface layer, release
layers are generally very thin layers which promote the separation of
layers. Materials useful as release layers are well known in the art.
Release layers discussed earlier with regard to the carrier element are
also useful here as long as the adhesion balances are met. Those which can
be used as the transfer surface layer(s) include, for example, silicones;
vinyl chloride polymers and copolymers; vinyl acetate polymers and
copolymers; plasticized polyvinyl alcohols; etc. The release surface may
constitute the transfer surface layer (18) or transfer surface layers (18)
and (19). When a separate release layer or layers are coated onto the
transfer support, the layer(s) generally has a thickness in the range of 1
to 10 micrometers.
The preferred type of transfer surface layer is a cushion layer having a
release surface. As with the carrier cushion layer, the transfer cushion
layer is a deformable layer which is generally thicker than a release
layer.
The transfer cushion layer should have a release surface to allow for
separation of the transfer support and transfer cushion layer from the
temporary coversheet (not shown), and from any layers which are
subsequently laminated to the transfer cushion layer. As mentioned above,
the composition of the transfer cushion layer should be chosen so as to
produce the appropriate adhesiveness relative to the release surface of
the carrier cushion layer. Examples of some suitable materials which can
be used as the transfer cushion layer include ethylene/vinyl acetate
copolymers; ethylene/methacrylic acid copolymers and ionomers, generally
having a higher methacrylic acid content than when used as a carrier
cushion layer; ethylene/acrylic acid copolymers and ionomers, generally
having a higher acrylic acid content than when used as a carrier cushion
layer; ethylene/methacrylate copolymers; ethylene/methacrylic
acid/isobutylacrylic acid ionomers, generally having a higher methacrylic
acid and isobutylacrylic acid content than when used as a carrier cushion
layer; and the like. Mixtures of materials can also be used. Preferred
materials for the transfer cushion layer are ethylene/vinyl acetate
copolymers. The transfer cushion layer can also include materials such as
surfactants, plasticizers, coating aids, and the like. In general,
colorants, antihalation dyes, optical brightener, etc., are not used in
the transfer cushion layer as they serve no added purpose in this layer.
The transfer cushion layer generally has a thickness in the range of about
25 to 150 micrometers (1 to 6 mils); preferably 75 to 125 micrometers (3
to 5 mils).
In order to ensure adequate adhesion of the transfer cushion layer to the
transfer support, it is sometimes necessary to include one or more anchor
layers between them. Adhesive materials for bonding different types of
materials are well known in the art and discussions can be found in, e.g.,
Handbook of Adhesives, 2nd Edition, Irving Skeist, Ed. (Van Nostrand
Reinhold Co., New York, 1977). Any conventional adhesive materials can be
used in the anchor layer or layers. Suitable materials for use as the
transfer anchor layer include, for example, ethylene/vinyl acetate
copolymers; vinyl chloride/vinyl acetate copolymers; vinyl
chloride/vinylidene chloride copolymers; thermoplastic polyamides; and the
like. The exact choice of adhesive will depend on the compositions of the
transfer cushion layer and the transfer support. The anchor layer or
layers can have incorporated therein materials such as antistats,
colorants, surfactants, plasticizers, coating aids, and the like.
The transfer anchor layer generally has a thickness in the range of 0.1 to
10 micrometers; preferably 0.5 to 2 micrometers. When more than one anchor
layer is present, the total thickness of the layers is generally in the
above range.
The optional temporary coversheet is present to protect the underlying
layers, if necessary, and must be easily removable. It can be selected
from any of the materials discussed above that are useful as the temporary
coversheet for carrier element.
PERMANENT SUPPORT ELEMENT
One advantage of the process of this invention is that the permanent
support for the final colored image can be chosen from almost any sheet
material desired. For most proofing applications a paper support is used,
preferably the same paper on which the image will ultimately be printed.
Virtually any paper stock can be used. Other materials which can be used
as the permanent support include cloth, wood, glass, china, most polymeric
films, synthetic papers, thin metal sheets or foils, etc. Almost any
material which will adhere to the adhesive layer (11) can be used as the
permanent support.
PROCESS STEPS
The process of the invention may be used to produce a single color image on
a permanent support or it may be used to make a multicolor image on a
permanent support using either the exposure-in-register process or the
laminate-in-register process.
Single Color Image
In the process of producing a single color image on a permanent support,
the colored image is first built up on the carrier support by exposing and
developing by washout, an unpigmented photosensitive layer (12) having
provided thereon at least one aqueous permeable, colorant-containing
composition (13), a transfer element having a release surface (16) is
laminated thereto, and the carrier element is peeled off and the element
is laminated to the permanent support (20).
Step A:
The element shown in FIG. 1 is prepared by applying at least one aqueous
permeable, colorant-containing composition (13) to a photosensitive
element comprising, in order, a carrier element having a release surface
(10), an adhesive layer (11), a first photosensitive layer (12), wherein
the colorant-containing composition is adjacent to the first
photosensitive layer (12). The colorant-containing composition (13) may be
applied by coating, spraying, laminating or printing. Preferably, the
composition (13) is printed using an ink jet printer. Advantages of the
invention are that the colorant-containing composition need not be applied
to the whole surface of the first photosensitive layer and more than one
colorant-containing composition can be applied to the first photosensitive
layer. The colorant-containing composition need only be applied in the
approximate areas where an image is to be formed in Steps B and C.
Step B:
The element shown in FIG. 1 is exposed to actinic radiation which is
absorbed by the photosensitive composition to activate the imaging
reaction in conventional fashion. "Actinic radiation" is any radiation
which produces imaging. The radiation can be natural or artificial,
monochromatic or polychromatic, incoherent or coherent. For efficient
image formation, most of the actinic radiation should be absorbed by the
photosensitive material. The absorption spectrum of the photosensitive
material may be determined by conventional spectrophotometry.
Conventional sources of actinic radiation that may be selected include
fluorescent, mercury vapor, mercury-xenon, metal additive, and arc lamps.
Useful sources of coherent radiation, such as lasers whose emissions fall
within or overlap the absorption bands of the photosensitive composition,
may also be used. Exposure is ordinarily carried out through a halftone
image-bearing transparency, preferably a halftone color separation
transparency. However, other means, such as a modulated scanning laser
beam, CRT (cathode ray tube), and the like, may be used to imagewise
expose the photosensitive elements.
The element is exposed to actinic radiation, typically through a separation
transparency with the emulsion side of the transparency in contact with
the aqueous permeable, colorant-containing composition, if it is present
as a layer on the photosensitive layer, or the photosensitive layer if the
aqueous permeable, colorant-containing composition is absorbed into the
photosensitive layer. Exposure is conveniently carried out in a standard
vacuum frame to ensure good contact between the transparency and the
photosensitive layer with its overlying aqueous permeable
colorant-containing composition.
Step C:
The next step is to develop the unpigmented photosensitive layer and its
overlying aqueous permeable, colorant-containing composition by washing
with an aqueous liquid. When the photosensitive layer is
photoinsolubilizable, the aqueous liquid removes only the unexposed areas
of the photosensitive layer and its overlying aqueous permeable,
colorant-containing composition. When the photosensitive layer is
photosolubilizable, the aqueous liquid removes only the exposed areas of
the photosensitive layer and its overlying aqueous permeable,
colorant-containing composition. As a result of the development step, a
first colored pattern comprised of (12') and (13') is formed.
It is preferred that the development step be effected using ordinary tap
water or the like to minimize concerns regarding toxicity, waste
treatment, and corrosion. Development can either be done manually or using
automated machines. It can be carried out at elevated temperatures, but in
most cases room temperature is preferred.
Step D:
The next step in the process is to laminate the transfer element (16),
shown in FIGS. 3 and 4, to the element formed above, as shown in FIG. 5.
The temporary coversheet, if present, is removed and the two elements are
laminated together such that the transfer surface layer (18) in FIG. 3,
transfer surface layer (19) in FIG. 4 or the transfer element having a
release surface (16) shown in FIG. 5 is adjacent to the first colored
pattern, i.e., the developed photosensitive layer and its overlying
aqueous permeable, colorant-containing composition comprised of (12') and
(13') as illustrated in FIG. 5.
The resulting element, called the intermediate imaged element, has the
structure shown in FIG. 5. The adhesion forces between the individual
layers have the following values:
F1=the adhesion force between the carrier support (10) and the adhesive
layer (11);
F2=the adhesion force between the adhesive layer (11) and the developed
photosensitive layer (12');
F3=the adhesion force between the first color pattern comprised of at least
one developed aqueous permeable colorant-containing composition (13') and
a developed photosensitive layer (12') and the transfer element having a
release surface (16);
Step E:
The next step in the process is to remove the carrier element having a
release surface (10). Thus the image is transferred to the transfer
element. This step is accomplished by peeling the transfer element and the
carrier element apart. In order to obtain the desired result, the adhesion
values F2 and F3 must each individually be greater than the adhesion value
F1.
Step F:
The next step in the process is to laminate the permanent support (20) to
the element from above, such that the permanent support (20) is adjacent
to the adhesive layer (11) as illustrated in FIG. 6. The adhesion force
between the permanent support (20) and the adhesive layer (11) has a value
F4.
Step G:
The next step in the process is to remove the transfer element having a
release surface (16), thereby transferring the image to the permanent
support. This step is accomplished by peeling the transfer support and the
permanent support apart. In order to obtain the desired result, the
adhesion values F2 and F4 must each individually be greater than the
adhesion value F3.
Multicolor Image Formation--Expose-in-register Process
When an image having more than one color is to be formed using the
expose-in-register process, the process begins with steps A through C as
described above, to form a first colored pattern. This is followed by
steps C1 through C6 prior to step D.
Step C1:
The next step in the process of forming a multicolor image is to laminate
an additional unpigmented photosensitive element to the developed element
from step C above. The additional element as shown in FIG. 7, has an
additional support (10a), an underlying additional photosensitive layer
(12a), and an underlying additional adhesive layer (11a) which is adjacent
to and overlying the first colored pattern comprised of the aqueous
colorant containing composition (13') and its underlying photosensitive
layer (12').
The adhesion forces between the layers have the values F1 and F2 as defined
above, and in addition:
F5=the adhesion force between the first colored pattern comprised of (12')
and (13') and the overlying additional adhesive layer (11a).
F6=the adhesion force between the additional adhesive layer (11a) and the
overlying additional photosensitive layer (12a) prior to exposure to
actinic light.
F7=the adhesion force between the additional photosensitive layer (12a)
prior to exposure to actinic light and the overlying additional support
(10a).
Step C2:
The additional support (10a) is removed from the additional photosensitive
layer (12a). In order to obtain the desired result, the adhesion values
F1, F2, F5, and F6, must each individually be greater than the adhesion
value F7.
Step C3:
As shown in FIG. 8, at least one additional aqueous permeable, colorant
containing composition (13a) is then applied to the additional
photosensitive layer (12a).
Step C4:
The next step in the process is to imagewise expose the additional
photosensitive layer (12a) with its overlying additional aqueous
permeable, colorant containing composition (13a) in register with the
first colored pattern comprised of (12') and (13'). Suitable registration
techniques are well known in the art and include pin and bar registration.
The exposure is carried out as described in Step B.
Step C5:
The next step in the process is to develop the element from step C4 using
aqueous washout development as described in step C. This results in the
formation of a second colored pattern comprised of (12a') and (13a').
Step C6:
Steps C1 to C5 are repeated in order, one or more times to provide
additional colors to the image. These steps are carried out using
additional unpigmented elements and additional aqueous permeable, colorant
containing compositions. The unpigmented element has an additional
adhesive layer (11b) and colored pattern (not shown), through the nth
element having an additional adhesive layer (11n) and an overlying colored
pattern comprised of (12n') and (13n') as shown in FIG. 9. In each
lamination step the unpigmented photosensitive element element described
in Step C1 is laminated to the element from Step C5 such that the
additional adhesive layer is adjacent to and overlying the outermost
colored pattern. It will be appreciated that for each repetition of Step
C3 in which the additional temporary support is removed, the adhesion
force between the additional temporary support and the underlying
unexposed additional photosensitive layer is less than the adhesion forces
between all of the other layers in the element.
Step D:
As illustrated in FIG. 9, the element from Step C6 is then laminated to the
transfer element having a release surface (16) such that its release
surface is adjacent to the outermost colored pattern comprised of (12n')
and (13n'). The resulting laminated element has a first colored pattern
(12') and (13') and n additional colored patterns. The adhesion forces
between the layers have the values F1, F2, F3 as defined above, and in
addition:
F2i=the adhesion force between the additional adhesive layer 11a and the
overlying additional color pattern comprised of (12a') and (13a').
F5i=the adhesion force between the additional colored pattern comprised of
(12a') and (13a') and the overlying additional adhesive layer (11b).
F3n=the adhesion force between the uppermost additional colored pattern
comprised of (12n') and (13n') and the transfer element (16).
In most cases, the same photosensitive composition will be used for all the
photosensitive layers, and the same adhesive composition will be used for
all the adhesive layers.
Step E:
The carrier element (10) is then removed. Adhesion values F2, F3, F2i, F3n,
F5 and F5i must be greater than the adhesion value F1 to achieve this
result.
Step F:
Permanent support (20) is then laminated to the element from Step E, such
that the permanent support is adjacent to the adhesive layer (11). This
results in the structure shown in FIG. 10. The adhesion force between the
permanent support (20) and the adhesive layer (11) has a value F4, as
previously defined.
Step G:
Transfer element having a release surface 16 is then removed, thereby
transferring the image to the permanent support as illustrated in FIG. 11.
This step is accomplished by peeling the transfer element and the
permanent support apart. In order to obtain this result, adhesion values
F2, F2i, F4, F5, and F5i each are greater than the adhesion value F3n. In
the embodiment shown in FIG. 11 no additional layers have been added to
the image structure as a result of the transfer steps. The only layers
present, other than the permanent support, are colored pattern comprised
of (12') and (13'), (12a') and (13b'), and (12n') and (13n') and
associated adhesive layers (11), (11a) and (11n).
Multicolor Image Formation--Laminate-in-register Process
When an image having more than one color is to be formed using the
laminate-in-register process, the process begins with steps A through E as
described above, to form a first colored pattern on a transfer element.
This is shown in FIG. 5 with the carrier element that is removed in Step E
still intact. Steps A-E are repeated to transfer an additional colored
pattern comprising at least one aqueous permeable colorant-containing
composition (13a'), and its underlying unpigmented photosensitive layer
(12a') formed by exposure and development of the element shown in FIG. 1,
and an underlying adhesive layer (11a) present on a carrier element (10a)
to the transfer element containing a first colored pattern comprising at
least one aqueous permeable colorant-containing composition (13'), and its
overlying unpigmented photosensitive layer (12') and an overlying adhesive
layer (11) as shown in FIG. 12.
Steps A-E may be repeated n times resulting in an element similar to that
shown in FIG. 13 with adhesive layer (11n) being the outermost layer and
having an underlying colored pattern comprised of the developed
unpigmented photosensitive layer (12n') and the developed aqueous
premeable colorant-containing composition (13n'). As shown in FIG. 14, the
multicolor image on the transfer element (16) is transferred to a
permanent receptor (20) followed by the removal of the transfer element.
The final multicolor proof formed is shown in FIG. 15.
The adhesion forces between the critical individual layers have the
following values:
F8=the adhesion force between the carrier support (10a) and the adhesive
layer (11a);
F3=the adhesion force between the first color pattern comprised of at least
one developed aqueous permeable colorant-containing composition (13') and
a developed photosensitive layer (12') and the transfer element having a
release surface (16).
F4=the adhesion force between the permanent support (20b) and the adhesive
layer (11).
The adhesion force F3 and adhesion forces between all colored patterns and
adjacent adhesive layers is greater than the adhesion force F8. The
adhesion force F4 and adhesion forces between all colored patterns and
adjacent adhesive layers is greater than the adhesion force F3.
It should be noted that both the carrier element and the transfer element
of the present invention can be used repeatedly to form several colored or
multicolored images.
INDUSTRIAL APPLICABILITY
The elements of this invention are useful for preparing colored images.
These images are particularly useful in the graphic arts field, especially
in the area of color proofing wherein proofs are prepared to predict the
images produced by printing.
The advantageous properties of this invention can be observed by reference
to the following examples which illustrate, but do not limit, the
invention.
EXAMPLES
______________________________________
GLOSSARY
______________________________________
Aurora Pink .RTM. EPX-11
Aqueous pigment dispersion; Day-
Glo Color Corporation
Denka .RTM. LAC TL-03
Vinyl chloride/vinyl acetate
copolymer; Denki Kagaku Kogyo
Kabushiki Kaisha
Dryer 900 P-Toluenesulfonic acid
Eastman AQ .RTM. 38D
Polyester emulsion; Eastman
Chemical Company
Iotek .RTM. 4080
Ethylene acrylic acid ionomer;
Exxon Chemicals, Houston, TX
Irgalite .RTM. Phthalocyanine green pigment;
Green GLN Ciba-Geigy, Pigments Div.,
Ardsley, NY
Mizukasil .RTM. SK7
Silica particles; Mizusawa
Industrial Chemicals
Ryuron .RTM. QU-628
Vinyl chloride/vinyl
propionate/vinyl acetate/methyl
methacrylate copolymer; Tosoh
Corporation
SPP M-20 Polyvinyl alcohol acetalized
with N-methyl-4-(p-formyl
styryl)pyridinium methosulfate;
Toyo Gosei Kogyo Co., LTD.
Sunsperse .RTM. Black
Aqueous pigment dispersion; Sun
LHD-9303 Chemical, Dispersions
Div., Amelia, OH
Sunsperse .RTM. Blue
Aqueous pigment dispersion; Sun
BHD-6000 Chemical, Dispersions Div.
Amelia, OH
Sunsperse .RTM. Blue
Aqueous pigment dispersion; Sun
BHD-6015 Chemical, Dispersions Div.
Amelia, OH
Sunsperse .RTM.
Aqueous pigment dispersion; Sun
Magenta QHD-6040
Chemical, Dispersions Div.
Amelia, OH
Sunsperse .RTM.
Aqueous pigment dispersion; Sun
Yellow YHD-9439
Chemical, Dispersions Div.
Amelia, OH
Tispeel XA51-824A
Melamine acrylic resin; Hitachi
Kasei Polymer, Japan
Vylonal MD Heat sealable polyester resin
emulsions; Toyobo Co., Japan
Zonyl .RTM. FSO-100
Perfluoroalkyl surfactant;
DuPont, Wilmington, DE
UGRA test strip
Dot range 0.5%-99.5% dots,
Graphic Arts Technical
Foundation, Pittsburgh, PA.
______________________________________
Example 1
Photosensitive Element:
The photosensitive film element used in this example had in order, the
following structure: (1) an approximately 1 micron photosensitive layer,
(2) a 1 micron adhesive layer (3) an approximately 3 micron release layer
(4) a 4-mil polyethylene terephthalate support. The photosensitive layer
was composed of SPP M-20. The adhesive layer was composed of a 30:70
mixture of Vylonal MD-1400 and Vylonal MD-1100. The release layer was
composed of Tispeel XA51-824A (4.9 parts by weight), Ryuron.RTM. QU-628
(93.2 parts by weight), Mizukasil.RTM. SK7 (1.5 parts by weight), and
Dryer 900 (0.4 parts by weight).
Aqueous Permeable, Colorant-Containing Composition Applied or "Inked"
Photosensitive Element:
The inked photosensitive element was prepared as described below.
Transfer Element:
The transfer element used was a commercially available WaterProof.RTM.
Transfer Sheet (manufactured by E. I. du Pont de Nemours and Co.,
Wilmington, Del.).
Process Steps:
Step 1.
An aqueous permeable, colorant-containing composition comprising a solution
of 1 part Sunsperse.RTM. Blue BHD-6015 and 49 parts water was applied or
"inked" onto the photosensitive layer by coating using a wire-wound rod.
Step 2.
The inked photosensitive element was placed in a vacuum frame with the ink
layer up, i.e., facing the source of actinic radiation. A negative
separation transparency for cyan was placed on top of the ink layer with
the emulsion side of the transparency in contact with the ink layer and
the base side up. A vacuum was drawn on the element and separation
transparency for about 90 sec prior to exposure. The element was exposed
for about 20 sec with the radiation from a 5 kW high pressure mercury
vapor lamp, (Olec L1261 lamp, Olec Olix AL985 Integrator and Olite
AL53-100 power supply, Olec, Inc., Irvine, Calif.) about 137 cm above the
element and separation transparency. After exposure, the separation
transparency was removed from the exposed photosensitive element.
Step 3.
The element was then developed and dried using a WaterProof.RTM. WashOff
Unit (DuPont) which utilized a 24.degree. C. water stream and rotating
brush to remove the non-exposed areas of the photosensitive and ink
layers. The element was then dried at a dryer temperature of approximately
110.degree. C.
Step 4.
The coversheet of the transfer element was removed by peeling. The
image-carrying element was placed on the revealed layer of the transfer
element with the image down and then laminated using a WaterProof.RTM.
Laminator (DuPont) at 100.degree. C., 150 lbs, 400 mm/min.
The photosensitive element support and release layer were next removed by
peeling, and thus, effectively transferring the cyan image to the transfer
element. The result was a wrong-reading cyan image on the transfer
element.
Step 5.
The cyan image on the transfer element was placed image down on a piece of
LOE paper stock and then laminated at 100.degree. C., 450 lbs, and 400
mm/min. The transfer element was then removed by peeling to reveal a
stain-free cyan proof on LOE paper. The proof image results are shown in
Table 1.
TABLE 1
______________________________________
Color UGRA UGRA UGRA
Color Density % Dots Resolution (.mu.)
50% Dot
______________________________________
Gain 1.39 0.5-99.5 6 15
Cyan
______________________________________
Example 2
Example 1 was repeated with the following differences: the aqueous
permeable, colorant-containing composition used was a solution of 3.8
parts Aurora Pink.RTM. EPX-11, 11.4 parts Eastman AQ.RTM. 38D, and 34.8
parts water. The aqueous permeable, colorant-containing composition
applied or "inked" element was exposed through a negative separation
transparency for magenta for 10 seconds. A pink image was formed instead
of a cyan image. The proof image results are shown in Table 2.
TABLE 2
______________________________________
Magenta Color UGRA UGRA
Color Density % Dots Resolution (.mu.)
______________________________________
Pink 0.44 2-98 8
______________________________________
Example 3
Film Elements.
The photosensitive and transfer elements were prepared according to the
procedure in Example 1.
Process Steps:
Step 1.
The photosensitive element was "inked" using a Hewlett Packard Desk Jet
550C ink jet printer. Three approximately 1".times.7" single-color, solid
ink strips of cyan, magenta and yellow inks were applied to the
photosensitive layer using the ink jet printer.
The inks used had the following compositions and were prepared using a
procedure similar to that described in Example 1 of U.S. Pat. No.
5,310,778 issued May 10, 1994:
______________________________________
AMOUNT
INGREDIENT (%)
______________________________________
Cyan Ink:
Monolite .RTM. Green 751 pigment, Zeneca, Inc.,
0.83
Wilmington, DE.
Endurophthal .RTM. Blue GF, Cookson Pigments, Inc.,
1.67
Newark, NJ.
Butyl methacrylate/methyl methacrylate/
1.67
methacrylic acid, (BMA/MMA//MAA) (10/5//10).sup.1
Diethylene glycol 5.70
Liponics .RTM. EG-1, Lipo Chemical Co., Paterson, NJ.
5.70
N-methyl pyrrolidinone 0.90
Deionized water 83.50
The ink had a pigment to binder ratio of 2:1.
Magenta Ink:
Quindo .RTM. Magenta RV6803, Miles, Inc.,
2.175
Pittsburg, PA.
Indofast .RTM. Brilliant Scarlet R6300, (Pigment Red
0.325
163, C.I. No. 71145), Miles, Inc., Pittsburg, PA.
Butyl methacrylate/methyl methacrylate/
1.67
methacrylic acid, (BMA/MMA//MAA) (10/5//10).sup.1
Diethylene glycol 5.70
Liponics .RTM. EG-1, Lipo Chemical Co., Paterson, NJ.
5.70
N-methyl pyrrolidinone 0.90
Deionized water 83.53
The ink had a pigment to binder ratio of 1.5:1.
Yellow Ink:
Permanent Yellow GG pigment, Hoechst Celanese,
2.50
Specialty Chemicals Group, Charlotte, NC.
Butyl methacrylate/methyl methacrylate//
1.67
methacrylic acid, (BMA/MMA//MAA) (10/5//10).sup.1
Diethylene glycol 5.70
Liponics .RTM. EG-1, Lipo Chemical Co., Paterson, N.J.
5.70
N-methyl pyrrolidinone 0.90
Deionized water 83.53
The ink had a pigment to binder ratio of 1.5:1.
______________________________________
.sup.1 Polymer 3 in U.S. Pat. No. 5,310,778. Made as described therein.
Step 2.
The inked photosensitive element was exposed for 50 sec, developed, and
then transferred to the transfer element as described in Steps 2-4 of
Example 1. The result was a set of wrong-reading cyan, magenta, and yellow
images on the transfer element.
Step 3.
The images on the transfer element were transferred to LOE paper stock as
described in Step 5 of Example 1. The result was a set of 3 single-color
images on LOE. Proof image results are shown in Table 3.
TABLE 3
______________________________________
Color UGRA UGRA
Color Density % Dots Resolution (.mu.)
______________________________________
Cyan 0.8 2-98 8
Magenta 0.6 2-99 6
Yellow 0.5 5-97 20
______________________________________
Example 4
Film Elements:
The photosensitive and transfer elements were prepared according to the
procedure described in Example 1.
Process Steps:
Step 1.
Four separate photosensitive elements were "inked" by individually coating
the following solutions onto separate photosensitive layers using a
wire-wound rod.
The aqueous permeable, yellow pigment-containing solution was comprised of
1 g Sunsperse.RTM. Yellow YHD-9439, 49 g water and 0.03 g Zonyl.RTM.
FSO-100.
The aqueous permeable, magenta pigment-containing solution was comprised of
1 g Sunsperse.RTM. Magenta QHD-6040, 49 g water and 0.03 g Zonyl.RTM.
FSO-100.
The aqueous permeable, cyan pigment-containing solution was comprised of 1
g Sunsperse.RTM. Blue BHD-6000, 49 g water and 0.03 g Zonyl.RTM. FSO-100.
The aqueous permeable, black pigment-containing solution was comprised of 1
g Sunsperse.RTM. Black LHD-9303, 49 g water and 0.03 g Zonyl.RTM. FSO-100.
Step 2.
The "inked" photosensitive elements were exposed for 14 (magenta), 20
(yellow), and 40 (cyan, black) sec through the corresponding negative
separation transparencies and then developed using a WaterProof.RTM.
WashOff Unit as described in Steps 2 and 3 of Example 1.
Step 3.
The black image was then transferred to the transfer element as described
in Step 4 of Example 1. The result was a wrong-reading black image on the
transfer element.
Step 4.
The cyan image was next registered over the wrong-reading black image on
the transfer element followed by transfer lamination of the cyan image as
described in Step 4 of Example 1. The result was a wrong-reading 2-color
image on the transfer element.
Step 5.
Step 4 was then repeated sequentially with each of the developed magenta
and yellow images to obtain a wrong-reading 4-color image on the transfer
element.
Step 6.
The wrong-reading 4-color image on the transfer element was then
transferred to LOE paper stock as described in Step 5 of Example 1. The
result was a right-reading 4-color proof on LOE paper stock.
Example 5
Film Elements:
The first photosensitive element had the following structure: (1) an
approximately 1 micron photosensitive layer, (2) a 1 micron adhesive
layer, (3) an approximately 50 micron cushion layer with a release surface
and (4) a 7-mil polyethylene terephthalate support. The photosensitive and
adhesive layers were the same as those described in Example 1. The cushion
layer was composed of Iotek.RTM. 4080 (about 98% by wt) and Irgalite.RTM.
Green GLN (about 2% by wt). The transfer element was the same as that
described in Example 1.
Process Steps:
Step 1.
The first photosensitive element was "inked" by coating a solution of 1 g
Sunsperse.RTM. Blue BHD-6000, 49 g water and 0.03 g Zonyl.RTM. FSO-100
onto the photosensitive layer using a wire-wound rod.
Step 2.
The inked first photosensitive element was exposed for 40 sec through a
negative separation transparency for cyan and then developed using a
WaterProof.RTM. WashOff Unit as described in Steps 2 and 3 of Example 1.
Step 3.
A second photosensitive element comprised of of adhesive and photosensitive
layers was then laminated, with the adhesive layer adjacent the developed
image on the first photosensitive element.
Step 4.
The second photosensitive layer was "inked" using the aqueous permeable,
yellow pigment-containing solution of Example 4.
Step 5.
The inked second photosensitive layer was next exposed for 40 sec through a
negative separation transparency for yellow in register over the cyan
image and developed as described in Steps 2 and 3 of Example 1. The result
was a right-reading 2-color image on the carrier element.
Step 6.
The right-reading 2-color image was then transferred to the transfer
element using the same conditions as described in Step 5 of Example 1. The
result was a wrong-reading 2-color image on the transfer element.
Step 7.
The wrong-reading 2-color image on the transfer element was then
transferred to LOE paper stock as described in Step 5 of Example 1. The
result was a right-reading 2-color proof on LOE paper stock.
Example 6
Film Elements:
Two photosensitive elements prepared according to the procedure described
in Example 1 were used. The transfer element was Fuji Color-Art Receiver
Film CR-T3.
Process Steps:
Step 1.
Two separate photosensitive elements were "inked" by individually coating
the following solutions onto separate photosensitive layers using a
wire-wound rod.
The aqueous permeable, magenta pigment-containing solution was comprised of
2 g Sunsperse.RTM. Magenta QHD-6040, 48 g water and 0.03 g Zonyl.RTM.
FSO-100.
The aqueous permeable, cyan pigment-containing solution was comprised of 1
g Sunsperse.RTM. Blue BHD-6000, 49 g water and 0.03 g Zonyl.RTM. FSO-100.
Step 2.
The "inked" photosensitive elements were each exposed for 40 sec through
the corresponding negative separation transparencies and then developed
using a WaterProof.RTM. WashOff Unit as described in Steps 2 and 3 of
Example 1.
Step 3.
The cyan image was then transferred to the transfer element as described in
Step 4 of Example 1. The result was a wrong-reading cyan image on the
transfer element.
Step 4.
The magenta image was next registered over the wrong-reading cyan image on
the transfer element followed by transfer lamination of the magenta image
as described in Step 4 of Example 1. The result was a wrong-reading
2-color image on the transfer element.
Step 5.
The wrong-reading 2-color image on the transfer element was then
transferred to LOE paper stock as described in Step 5 of Example 1. At
least one layer of the transfer element also transferred with the 2-color
image, yielding a right-reading 2-color proof with high gloss on LOE paper
stock.
Having described the invention, we now claim the following and their
equivalents.
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